Genius

Almost always no. Depending on the app and the developer, you usually don't. If you're using a device that was previously jailbroken that you purchased the apps from it is usually recognized by Cydia and your licenses carry over. If it's a new device you can go to Manage Account in Cydia, input your credentials, and be good to go. In some cases the developers will charge an upgrade fee to license holders if they put a ton of work into an app updating for a new iOS/jailbreak. I think IntelliscreenX and MyWi are examples this time around. So far i haven't had to pay for any of my paid apps again. YMMV.

Member

Almost always no. Depending on the app and the developer, you usually don't. If you're using a device that was previously jailbroken that you purchased the apps from it is usually recognized by Cydia and your licenses carry over. If it's a new device you can go to Manage Account in Cydia, input your credentials, and be good to go. In some cases the developers will charge an upgrade fee to license holders if they put a ton of work into an app updating for a new iOS/jailbreak. I think IntelliscreenX and MyWi are examples this time around. So far i haven't had to pay for any of my paid apps again. YMMV.